1. Field of the Invention
The present invention relates generally to an apparatus for shearing of extruded stock and the like and, more particularly, to an apparatus for twist-shearing of extruded stock into sections of predetermined length.
2. Description of the Related Art
Elongated stock material is frequently cut into sections of predetermined length to form articles such a brackets, braces, spacers, clamps and other parts. Such elongated stock is often produced by extrusion and, thus, is of a constant cross section throughout its length. It is also possible, however, that the elongated stock has been produced by drawing, such as for pipe or wire, by rolling, such as for bar stock, or by other techniques. The elongated stock material is generally of constant cross-sectional shape, although it is possible that it has been machined before being cut and so has variations in its shape. For purposes of the present invention, the term extruded stock shall include each of the foregoing types of elongated stock, as well as other types which may pass through a twist-shearing die and, thus, come within the scope of the present invention.
The most common method for cutting extruded or elongated stock is by sawing. However, sawing produces burrs at the cut line, generates heat, dust, grit and noise, and wastes material, since up to one eighth inch of material may be lost for each cut. The stock must be clamped firmly in place during sawing to insure an even and square cut, and such clamping may result in denting or otherwise damaging or deforming thin walled stock. Due to the high speed operation of the saws, operators must wear safety goggles, face protectors and ear protectors.
Rotating die cut-off machines are known in the art in which a rotating die is rotated relative to a stationary die about 360.degree. to shear or cut-off lengths of extruded stock which is passed through openings in the two dies. Although such devices overcome many disadvantages of sawing, these devices tend to be slow.